In general, card-on-board electronic systems, such as so called Blade centers, are multi-server systems holding a plurality of servers. The servers can be dedicated individually to users or could be coupled building a higher performing SMP (SMP=Symmetric Multiprocessing System) server, or in High-Performance-Computing application could be linked by high-speed network thus building up a large scale server cluster.
A typical Blade cabinet is accommodating multiple 19-inch sized blade chassis. Each chassis itself can be populated with up to e.g. 14 single wide Blades. The expression “single wide” refers to a standard size of one unit in a standard chassis. Besides single wide Blades, double or multi wide Blades are also known which require the double and multiple width of a single wide unit, respectively. A Blade is an electronic board typically holding the entire core electronics required to represent a server. The Blades plugged into the Blade chassis can be of widely varying performance and I/O capability (I/O=Input/Output). Such Blades offer e.g. utilizing advanced server CPU's (CPU=Central Processing Unit), or multi-core CPU's, or advanced processors of various manufacturers. The standardized connectors of the Blades enable to populate a Blade Center (BC) to customer requirements in any mix of different Blade types.
As described, a typical BC chassis can be populated with up to 14 single wide Blades. For this reason, each chassis is provided a backplane planar board in the size accommodating the connectors to support 14 Blade positions. The backplane is oriented perpendicular to the front face of the Blades. Depending on the provider, this backplane planar board can feature the connectors for the Blades on the front side. In addition, it is possible to provide connectors on the rear side allowing plugging in various switch/network modules from the rear. Such a backplane is called the BC ‘midplane’.
The BC midplane printed circuit wiring is connecting the inputs and outputs (I/O) of each Blade position to the connectors of the mentioned various network and switch modules. In addition, the midplane is interconnecting wiring each Blade to the BC Management Modules, and, last not least, is providing DC power for each pluggable front and rear module.
Standardized systems are a precondition for allowing to build-up the described customer specific BC multi-server systems choosing form a wide variety of modules—but, on the downside, standard systems are restricted to the connectivity provided by the standardized interfaces.
New system designs, requiring by the present standard revision not foreseen connectivity or functions, most likely are forced to develop new complex sumptuous connectivity solutions, typically going along with significant cost adders for the final product. The new requirements can influence a new standard definition in progress, however, new standard releases are typically dismissed in longer time interval. However, a new system design usually cannot tolerate such a time delay.
Prevalently, new system designs require new/additional bus-connectivity utilizing high-speed links to the network modules, or even more urgent, require specific high-speed links to ‘neighborhood’ Blade positions. Typical solutions for example are cable assembly connections, which are either bulky and physically difficult to fit or suffer from lossy signal propagation and signal integrity problems.